High-resolution 4-D seismic data are providing time-lapse 3-D images of carbon dioxide (CO2) movement through a 900 m deep 4 m thick, oomoldic limestone, Lansing-Kansas City formation oil reservoir in central Kansas. Considering the lateral and vertical variability of properties in reservoirs of this type, understanding the effects of CO2 injection on phase behavior and gas and oil phase movement is critical to optimizing recovery and predicting long-term reservoir properties. An unconventional approach to data acquisition resulted in shot gathers with dominant frequencies above 140 Hz at 700 ms, providing a vertical bed resolution potential of around 4 m. Due to vertical permeability distribution, CO2 injection is focused into a 2 m thick zone of this reservoir where water flood enhanced oil recovery has dropped below economic levels. By optimizing acquisition, a recording system with only 240 channels coupled with a single low power, high frequency vibrator resulted in a highly repeatable and high S/N data set at a minimal cost. Changes in reflection amplitudes on shot gathers, interpreted to be from a depth range that includes the reservoir, are due to CO2 movement through the C zone of this reservoir. Production schemes must be developed that are dynamic and appropriate for the individual field for mature mid-continent oil reservoirs of this type to respond most efficiently to CO2 flooding. From a sequestration perspective it is important to establish that 4-D seismic imaging can provide the necessary containment assurances for shallow storage reservoirs and at a reasonable cost. These data are beginning to help improve the understanding of fluid-flow paths, reservoir architecture, reservoir properties, and CO2 movement for this 10-acre CO2 miscible flood, which began in Fall 2003. Over the life of this pilot study more than 12, 3-D seismic surveys will be conducted with later data sets instrumental to determining CO2 containment and post-injection CO2 stability.
|Published - 2004
|2004 Society of Exploration Geophysicists Annual Meeting, SEG 2004 - Denver, United States
Duration: Oct 10 2004 → Oct 15 2004
|2004 Society of Exploration Geophysicists Annual Meeting, SEG 2004
|10/10/04 → 10/15/04
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